Refrigerating apparatus



Feb. 24, 1931. c. F. KETTERING ET Al. 1,793,857

REFRIGERATING APPARATUS Filed Aug. 19, 1926 2 Sheets-Sheet 1 @mais Feb. 24, v1931. c. F. KETTERING ET A1.

REFRIGERAT ING APPARATUS Filed Aug- 19. 1926 2 Sheets-Sheet 2 i.' HIIIJI Patented Feb. 2.4,' 1931 UNITED STATES PATENT OFFICE CHARLES F. KETTERING-AND OTTO M. SUMMERS, OF DAYTON, OHIO, ASSIGNOBS, BY

,'MESNE ASSIGNMENTS, TO FRIGIDAIRE CORPORATION, A CORPORATION OF DELA- WARE REFRIGERATING APPARATUS Application tiled August 19, 1926. Serial No. 130,242.

to temperature changes, but not affected by mechanical vibration. One manner of carrying out this object is to provide a relatively long, stiff thermostatic blade, the free end of which will move a relatively great distance in response to slight variations in temperature, but will not be vibrated excessively due to vibrations of the support for the blade. In addition, the blade is submerged in a relatively viscous liquid in order to dampen vibration due to external causes.

Another object of the present invention is to simplifythe construction of a temperature responsive switch and to provide for the ready manufacture and repair thereof. This object is accomplished by constructing the switch'. contacts and thermostat as a unit which may be inserted or withdrawn from the apparatuswith which it is associated.

Another object of the invention is to provide for the positive opening and closing of the switch contacts, and to` provide a time lag or delay in the actuation of the contacts of the motor controlling switch for a period suf ficient to permit a certain, variaton in the temperature of the thermostat blade. In this way, minor temperature variations of relatively short, duration may occur without causing the rcfrigerating cycles to occur too frequently. v

Further objects and advantages of the present invention will be 'apparent from the following description, reference being had to the accompanying drawings, whereln a preferred form of the present invention is clearly shown.

In the drawings:

Fig. l is a diagrammatic view of a refrigerating system operatively connected with an i ice-cream cabinet and with the present invention applied thereto;

Fig. 2 isa fragmentary sectional view of a portion of the control mechanism;

Fig. 3 is a fragmentary sectional view of the refrigerator showing another portion of the control mechanism;

Fig. 4 is a View of the control mechanism shown in Fig. 3, looking in the direction of the arrow 4; A

Fig. 5 is a fragmentary View of the control mechanism, looking in the direction of arrow 5 of Fig. 3; and

Fig. 6 is a fragmentary top plan view,

partly in section, showing the location of the control mechanism shown in Fig. 3, with respect to the food container of the cabinet.

Referring to the drawings, for the purpose of illustrating the present invention there is shown an ice-cream cabinet 20,'including a brine tank 21, the top wall of which is provided with two rows of openings to receive ice-cream sleeves 22, which in turn are adapted to receive Vice-cream cans or the like. An evaporator 24 is immersed within the brine for cooling same. Thus the brine tank 2l and evaporator vvprovide a cooling unit for cooling the sleeves 22 and the contents thereof. Evaporator 24 is provided withan inlet coupling 25 and an outlet coupling 26 connected, respectively, with pipes 27 and 28. Pipe 28 is connected with the 'low-pressure side of compressor 30, while pipe 27 is con! nected with a condenser 31 which in turn is connected by a'pipe 32 with the high-pressure side of compressor 30. A motor 33 is connected with compressor 3() by belt-andpulley connections 34, 35 and 36.

`The circuit to themotor 33 includes wire 38, wire 39, contacts 40 and 41 and wire 42.- Contacts 40 and 4i are controlled by a snap switch 43 and the snap switch is controlled by the movement of a wall 44 of a metal bellows 45. The bellows 45 provides a chamber 46 adapted to contain a volatile fluid which when heated to a predetermined extent will cause the expansion of the bellows and such movementof the wall 44 operates the snap switch 43, which in turn will cause contact 41 te engage 40 and thereby compiete the circuit to the motor. For the purpose of illustration, the bottom wall,48 of the metal bellows 45 is depressed `to provide a housing 49 adapted to receive a lamp 50 which is connec'ted by a socket 51 with Wires 52 and 53. The circuit to the lalnp 50 is controlled by a thermostatic switch Whichis contained within a container 55, which container has a portion thereof immersed in the brine within the tank 21. Wire 53 is connected with a certain portion ofthe thermostatic switch and an.- other portion of the switch is connected. by a wire 56 to the wire 43. Wire 52 is connected to wirel 38 and when the circuit is completed by the thermostatic switch, the lamp 5() will be energized causing the fluid within the chamber 46 to be heated whereby to start the operation of the motor. Conversely, when the thermostatic switch opens the' circuit to-the lamp 50, the fluid within chamber 46 will cool and move the `switch 43 to interrupt the-motor circuit.

The bnn@ tank 21 is provide-a with mi opening `58 `in the top thereof through 'which the container 55 can be inserted. The upper end of the container i's provided with a flange 100 adapted to rest upon the brine tank 21. The upper end 'of the container 55 is also tapered so as to provide a seat 59 for a plug 6() of insulating material. An opening 61 is provided in the insulation 62 of the cabinet, whichopening is in alignment with the opening 58 in the brine tank 2l. Conduit 64 eX- tends through a wall of the cabinet and con nects with opening 61 and is arranged to receive wires 53 and 56.

The thermostatic switch65 hertofore mentioned for controlling the circuit to lamp 50, comprises a unit which is adapted to be inserted through the openings 61' and 58 and into thecontainer'. Thermostatic switch 65 includes a vertically-disposed, channelshapedrmember 66. The plug 60 for the container is clamped between a ange 71 of member 66 anda plate67 in any suitable manner, such as by -screws 68 and terminals 69 and 70. These terminals 69 and 70 are connected, respectively,`with Wires 53 and 56. Channel 66 extends to substantially the bottom of the container 55 and carries at its lower end an insulating block 72 which in turn ried by channel 66. lVithin the channel portion 80 of member 66 there is carried a permanent magnet 81 having a keeper 82 and which is adapted to modify the movement of thermostat 73, there being an armature 83 carried by the bi-metal blade 73 which is adapted to be attracted 'by magnet 81 when the blade 7 3V has moved said armature to a certain position.l A bell crank lever 84 is suitably pivoted at 85 to a support 86 carried by the member 66. One arm 87l of lever 84 is arranged to engage a pin 88, preferably constructed of hard insulating material, such as l 84 is perforated to receive a rod 91 which rod is provided with an abutment 92, utilized for the purpose of moving the arm 90 downwartlly. rlhe upper end of rod 91 is screwed within the plate 68 and is provided witha knurled head 94 for moving the rod upwardly and downwardly to thus decrease and increase distortion of blade 73. rThe container 55 is adapted t'o contain a viscous fluid, such as oil, the level of which is indicated at 95. Since the blade 73 is 'relatively long it is more or less subjected to vibrations and the purpose ofthe oil within the container is to impede the vibrations of said blade. This oil also functions as a heat conductor whereby the blade 73 is maintained at .substantial brine temperature. y

rlhe relatively long thermostat blade 73 is responsive to slight changes in temperature in the brine. An increase in temperature in -the brine causes the bi-metal blade 73 to operation of the motor. When contacts 76 and 77 are inengagement, the circuit will be completed to the lamp 50, which will cause the motor to be started, as previously described. The armature 83-will remain in contact with the keeper 82 until the temperature of `the brine is such that'when the armature is released, the contact 76 will separate quickly from the contact 77, the thermostat having sufiicient power to overcome the force of the magnet.

From the foregoing description it is apparent that a system has been provided for maintaining a unit at a substantially ,con-` stant temperature. By providing a relative- .ly long blade which is sensitive to slight changes in temperature and by preventing the same when subjected to vibration from effecting a chattering or rapid intermittent contact. a control has been provided, whose elements, while responsive to slight variations of temperature, are of rugged construe-.-

tion. This contact-making thermostat when used 'in combination with the heatv operated switch-actuating mechanism constitutes av -change of relatively permanent nature occnrs. .The metal bellows 45 and the fluid thereincontained, as well as the size of the heating 'element 50 should be so proportioned that an appreciable length of time is-required before the motor circuit is broken. Transient or momentary temperature fluctuations will therefore not cause the operation of the compressor and by eliminating these so-called short cycles, considerable economy in operation is effected.

It will be noted that the container 55 for therinostatic switch 65 is located adjacent an end wall of cabinet and, therefore, only a short conduit 64 need be provided in the insulation of cabinet 20. for wires 53 and 56. Thus said wire can be readily forced throulfh the relatively small-diameter conduit. T e relatively long container 55 is located between and arranged parallel with a pair of 20 sleeves 22 whereby the opening in the container is at the top. In this manner the switch 65 can be readily removed. The unit construction of the thermostatic switch facilitates the manufacture and repair of this system. In order to repair the thermostatic switch it is necessary only to remove an insulated plug `96 and insulation 97, which latter may be fibrous material, such as kapok, and then disconnect wires 53 and 56 from terminals 69 and 70, then, the entire thermostatic switch can be removed from the container 55 by hooking a wire or the like within the eye 98 of an ear 99, which ear is secured to plate 67.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims'which follow.

What is claimed is as follows: 1. A refrigerating system comprising, in combination, a cooling unit having an opening; means for circulatinga refrigerant medium through said unit; mechanism for controlling said means; a circuit for controlling said mechanism; a container insertable through "said opening and having an opening accessible from the exterior of said unit; and a switch carried 'within said container and responsive to the temperature of said unit for controlling said circuit.

2. A refrigerating system comprising. in combination, a cabinet; a cooling unitvwithiu vthe cabinet, and having an opening; means for circulating a refrigerant medium through said unit; a container Within the unit insertable through said opening and having an opening accessible from the exterior of the unit; and mechanism for controlling said,

means including a thermostat carried within lsaid container and removable through the p opening therein.

"3. A refrigerating system comprising, in combination, a cabinet having open-top food compartments; a cooling unit within the cabinet and having an opening disposed between a pair of sald compartments; means for circulating a refrigerant medium through said Y 

